U.S. patent application number 13/036683 was filed with the patent office on 2011-10-27 for communications system, carrier-side communication apparatus, base station apparatus, and communication method therefor.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Hiromitsu KAWAI, Daisuke NITTA, Tadanori YOKOSAWA.
Application Number | 20110261683 13/036683 |
Document ID | / |
Family ID | 44343228 |
Filed Date | 2011-10-27 |
United States Patent
Application |
20110261683 |
Kind Code |
A1 |
NITTA; Daisuke ; et
al. |
October 27, 2011 |
COMMUNICATIONS SYSTEM, CARRIER-SIDE COMMUNICATION APPARATUS, BASE
STATION APPARATUS, AND COMMUNICATION METHOD THEREFOR
Abstract
In a communications system, a first upper node performs
communication through a first communication session, and a second
upper node performs communication through a second communication
session. An upper communication control unit controls those upper
nodes. A first communication unit communicates with the first upper
node through the first communication session established therewith.
A second communication unit communicates with the second upper node
through the second communication session established therewith. A
communication control unit controls those communication units. The
communication control unit and the upper communication control unit
perform communication path switching so as to use the second
communication session to transport a signal intended for the first
communication session, when the first communication sessions is
disrupted, or when the number of existing first communication
sessions has reached an upper limit that the first upper node can
handle.
Inventors: |
NITTA; Daisuke; (Kawasaki,
JP) ; KAWAI; Hiromitsu; (Kawasaki, JP) ;
YOKOSAWA; Tadanori; (Kawasaki, JP) |
Assignee: |
FUJITSU LIMITED
Kawasaki-shi
JP
|
Family ID: |
44343228 |
Appl. No.: |
13/036683 |
Filed: |
February 28, 2011 |
Current U.S.
Class: |
370/225 |
Current CPC
Class: |
H04W 84/045 20130101;
H04W 36/0066 20130101; H04W 76/20 20180201 |
Class at
Publication: |
370/225 |
International
Class: |
H04W 40/00 20090101
H04W040/00; H04W 88/08 20090101 H04W088/08 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2010 |
JP |
2010-101101 |
Claims
1. A communications system comprising: a carrier-side communication
apparatus comprising: a first upper node to perform communication
through a first communication session, a second upper node to
perform communication through a second communication session, and
an upper communication control unit to control the first upper node
and the second upper node; and a base station apparatus comprising:
a first communication unit to communicate with the first upper node
through the first communication session established therewith, a
second communication unit to communicate with the second upper node
through the second communication session established therewith, and
a communication control unit to control the first communication
unit and the second communication unit; wherein the communication
control unit and the upper communication control unit are
configured to perform communication path switching so as to use the
second communication session to transport a signal intended for the
first communication session, when the first communication session
is disrupted, or when a number of existing first communication
sessions has reached an upper limit that the first upper node can
handle.
2. The communications system according to claim 1, wherein: the
communication controller and the upper communication controller are
responsive to an event that sets up a new first communication
session between the first communication unit and the first upper
node and starts communication therethrough; in response to the
event, the communication control unit causes the first
communication unit to send an uplink signal of the new first
communication session to the first upper node and also causes the
first and second communication units to send the same uplink signal
to the second upper node through a new second communication
session; and in response to the event, the upper communication
control unit causes the first upper node to send a downlink signal
for the new first communication session to the first communication
unit and also causes the first and second upper nodes to send the
same signal to the second communication unit through the new second
communication session.
3. The communications system according to claim 1, wherein: the
second communication unit encapsulates an uplink signal intended
for the first communication session into a signal to be transmitted
to the second upper node through the second communication session;
and the second upper node encapsulates a downlink signal intended
for the first communication session into a signal to be transmitted
to the second communication unit through the second communication
session.
4. A communication apparatus positioned at an upper carrier level,
comprising: a first upper node to communicate with a base station
through a first communication session; a second upper node to
communicate with the base station through a second communication
session; and an upper communication control unit to control the
first upper node and the second upper node, the upper communication
control unit being configured to perform communication path
switching so as to use the second communication session to
transport a signal intended for the first communication session,
when the first communication session is disrupted, or when a number
of existing first communication sessions has reached an upper limit
that the first upper node can handle.
5. A base station apparatus, comprising: a first communication unit
to communicate with an upper carrier network through a first
communication session established therewith; a second communication
unit to communicate with the upper carrier network through a second
communication session established therewith; and a communication
control unit to control the first communication unit and the second
communication unit, the communication control unit being configured
to perform communication path switching so as to use the second
communication session to transport a signal intended for the first
communication session, when the first communication session is
disrupted, or when a number of existing first communication
sessions has reached an upper limit that the upper carrier network
can handle.
6. A method of communication over communication sessions
established between a carrier-side communication apparatus and a
base station apparatus, the method comprising: performing
communication through first and second communication sessions
established between the carrier-side communication apparatus and
the base station apparatus; and performing communication path
switching so as to use the second communication session to
transport a signal intended for the first communication session,
when the first communication session is disrupted, or when a number
of existing first communication sessions has reached an upper limit
that the carrier-side communication apparatus can handle.
7. A communications system comprising: a carrier-side communication
apparatus comprising: a W-CDMA node to perform communication
through a W-CDMA communication session, an LTE node to perform
communication through an LTE communication session, and an upper
communication control unit to control the W-CDMA node and the LTE
node; and a base station apparatus comprising: a W-CDMA
communication unit to communicate with the W-CDMA node through the
W-CDMA communication session established therewith, an LTE
communication unit to communicate with the LTE node through the LTE
communication session established therewith, and a communication
control unit to control the W-CDMA communication unit and the LTE
communication unit; wherein the communication control unit and the
upper communication control unit are configured to perform
communication path switching so as to use the LTE communication
session to transport a signal intended for the W-CDMA communication
session, when the W-CDMA communication session is disrupted, or
when a number of existing W-CDMA communication sessions has reached
an upper limit that the W-CDMA node can handle, and wherein the
communication control unit and the upper communication control unit
are configured to perform communication path switching to use the
W-CDMA communication session to transport a signal intended for the
LTE communication session, when the LTE communication session is
disrupted, or when a number of existing LTE communication sessions
has reached an upper limit that the LTE node can handle.
8. The communications system according to claim 7, wherein: the
communication controller and the upper communication controller are
responsive to an event that sets up a new W-CDMA communication
session between the W-CDMA communication unit and the W-CDMA node
and starts communication therethrough; in response to the event,
the communication control unit causes the W-CDMA communication unit
to send an uplink signal of the new W-CDMA communication session to
the W-CDMA node and also causes the W-CDMA and LTE communication
units to send the same uplink signal to the LTE node through a new
LTE communication session; and in response to the event, the upper
communication control unit causes the W-CDMA node to send a
downlink signal for the new W-CDMA communication session to the
W-CDMA communication unit and also causes the W-CDMA and LTE nodes
to send the same signal to the LTE communication unit through the
new LTE communication session.
9. The communications system according to claim 7, wherein: the
communication controller and the upper communication controller are
responsive to an event that sets up a new LTE communication session
between the LTE communication unit and the LTE node and starts
communication therethrough; in response to the event, the
communication control unit causes the LTE communication unit to
send an uplink signal of the new LTE communication session to the
LTE node and also causes the W-CDMA and LTE communication units to
send the same uplink signal to the W-CDMA node through a new W-CDMA
communication session; and in response to the event, the upper
communication control unit causes the LTE node to send a downlink
signal for the new LTE communication session to the LTE
communication unit and also causes the W-CDMA and LTE nodes to send
the same signal to the W-CDMA communication unit through the new
W-CDMA communication session.
10. The communications system according to claim 7, wherein: the
LTE node encapsulates a downlink signal intended for the W-CDMA
communication session into a signal to be transmitted to the base
station apparatus through the LTE communication session, when the
W-CDMA communication session is disrupted, or when the number of
existing W-CDMA communication sessions has reached the upper limit
thereof; and the W-CDMA node encapsulates a downlink signal
intended for the LTE communication session into a signal to be
transmitted to the base station apparatus through the W-CDMA
communication session, when the LTE communication session is
disrupted, or when the number of existing LTE communication
sessions has reached the upper limit thereof.
11. The communications system according to claim 7, wherein: the
LTE communication unit encapsulates an uplink signal intended for
the W-CDMA communication session into a signal to be transmitted to
the carrier-side communication apparatus through the LTE
communication session, when the W-CDMA communication session is
disrupted, or when the number of existing W-CDMA communication
sessions has reached the upper limit thereof; and the W-CDMA
communication unit encapsulates an uplink signal intended for the
LTE communication session into a signal to be transmitted to the
carrier-side communication apparatus through the W-CDMA
communication session, when the LTE communication session is
disrupted, or when the number of existing LTE communication
sessions has reached the upper limit thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority of the prior Japanese Patent Application No. 2010-101101,
filed on Apr. 26, 2010, the entire contents of which are
incorporated herein by reference.
FIELD
[0002] The embodiments discussed herein relate to a communications
system that performs data communication, as well as to a
carrier-side communication device, a base station apparatus, and a
communication method therefor.
BACKGROUND
[0003] Third generation (3G) mobile communications systems using
wideband code-division multiple access (W-CDMA) techniques have
rapidly gained popularity, and their outdoor population coverage
has reached almost 100 percent. Their indoor population coverage,
on the other hand, is not so high as the outdoor coverage because
of the presence of obstacles to radio propagation and additional
operating cost of indoor base stations.
[0004] Recent years have seen an increased interest in miniature
radio base stations called "femtocells." Femtocells are suitable
for use in home and office environments, and many of them are
designed on the basis of 3G technology. For example, a femtocell
enables about four users within several tens of meters to enjoy
communication services simultaneously. Femtocells may be deployed
in high-rise buildings and residential towns to enhance the indoor
coverage of mobile services without having significant impact on
the cost of operations. In addition to 3G femtocells noted above,
femtocells adapted to the Long Term Evolution (LTE) standard have
also been developed, which are sometimes referred to as 3.9G
systems. 3G femtocells establish an Iuh session to an upper-level
network device for the purpose of call connection. LTE femtocells
establish an S1 session to an upper-level network device.
[0005] In this technical field, one proposed technique provides an
IPsec tunnel, not between a terminal device and a base station, but
only between the base station and gateway when supporting handoff
of the terminal device (see Japanese Laid-open Patent Publication
No. 2009-94651). According to another proposed technique, a
femtocell accepts a session switching request from a mobile
terminal. In response, the femtocell assigns other base station to
the requesting mobile terminal and then commands the mobile
terminal to release its radio connection to the femtocell (see
Japanese Laid-open Patent Publication No. 2010-16602). Yet another
proposed technique enables an IP multimedia subsystem (IMS) network
to directly serve 3G circuit-switched (CS) terminals, as well as
realizing a bearer protocol conversion (see Japanese Laid-open
Patent Publication No. 2008-205698).
[0006] Femtocells may be designed to support both 3G and LTE
technologies. Such femtocells are referred to as dual femtocells. A
dual femtocell includes 3G and LTE gateways to handle both the 3G
and LTE communication protocols, and Iuh and S1 sessions are
established with the 3G and LTE gateways, respectively.
[0007] A communications system may employ dual femtocells with
multiple radio access technologies (RAT) such as 3G and LTE. In
this system, however, some failure in one gateway facility would
immediately result in a breakdown of communication in its
corresponding RAT if the system does not have communication path
switching capabilities or redundant communication channels. That
is, a failure in a 3G gateway would disrupt ongoing 3G
communication, and a failure in an LTE gateway would disrupt
ongoing LTE communication. This could be a drawback of the system
in which the 3G and LTE networks operate independently of each
other.
[0008] As can be seen from the above discussion, the lack of
appropriate communication path switching capabilities makes it
impossible for the communications system to recover from disruption
of communication. The communications system cannot help but stop
its communication services.
[0009] Another drawback of the above-described system is that the
traffic load cannot be distributed among the gateways that support
different RATs. For example, even if the 3G gateway encounters an
excessive load, the system is unable to distribute the load to its
LTE gateway. This means that the system has a weakness in its
operability.
SUMMARY
[0010] According to an aspect of the invention, there is provided a
communications system which includes a carrier-side communication
apparatus and a base station apparatus. The carrier-side
communication apparatus includes a first upper node to perform
communication through a first communication session, a second upper
node to perform communication through a second communication
session, and an upper communication control unit to control the
first upper node and the second upper node. The base station
apparatus includes a first communication unit to communicate with
the first upper node through the first communication session
established therewith, a second communication unit to communicate
with the second upper node through the second communication session
established therewith, and a communication control unit to control
the first communication unit and the second communication unit. The
communication control unit and the upper communication control unit
are configured to perform communication path switching so as to use
the second communication session to transport a signal intended for
the first communication session, when the first communication
session is disrupted, or when the number of existing first
communication sessions has reached an upper limit that the first
upper node can handle.
[0011] The object and advantages of the invention will be realized
and attained by means of the elements and combinations particularly
pointed out in the claims.
[0012] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are not restrictive of the invention, as
claimed.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 illustrates an example structure of a communications
system;
[0014] FIGS. 2 and 3 illustrate an example of overall structure of
the radio communications system;
[0015] FIG. 4 illustrates a sequence of LTE communication using a
3G-side communication path;
[0016] FIG. 5 illustrates another sequence of LTE communication
using a 3G-side communication path;
[0017] FIG. 6 illustrates yet another sequence of LTE communication
using a 3G-side communication path;
[0018] FIG. 7 illustrates still another sequence of LTE
communication using a 3G-side communication path;
[0019] FIG. 8 illustrates a sequence of 3G communication using an
LTE-side communication path;
[0020] FIG. 9 illustrates another sequence of 3G communication
using an LTE-side communication path;
[0021] FIG. 10 illustrates yet another sequence of 3G communication
using an LTE-side communication path;
[0022] FIG. 11 illustrates still another sequence of 3G
communication using an LTE-side communication path;
[0023] FIG. 12 illustrates a sequence of LTE communication using a
3G-side communication path as a redundant communication path;
[0024] FIG. 13 illustrates a sequence of 3G communication using an
LTE-side communication path as a redundant communication path;
[0025] FIG. 14 illustrates a data format of a communication
disruption notice;
[0026] FIG. 15 illustrates a data format of a response to the
communication disruption notice;
[0027] FIG. 16 illustrates a data format of a session switching
request;
[0028] FIG. 17 illustrates a data format of a response to the
session switching request;
[0029] FIG. 18 illustrates a data format of an excessive session
notice;
[0030] FIG. 19 illustrates a data format of a response to the
excessive session notice;
[0031] FIG. 20 illustrates a data format of a redundant path setup
request;
[0032] FIG. 21 illustrates a data format of a response to the
redundant path setup request;
[0033] FIG. 22 illustrates a data format of control messages;
[0034] FIG. 23 illustrates protocol stacks of Iuh;
[0035] FIG. 24 illustrates protocol stacks of S1; and
[0036] FIG. 25 illustrates a protocol stack of TR-069.
DESCRIPTION OF EMBODIMENTS
[0037] Preferred embodiments of the present invention will be
described below with reference to the accompanying drawings,
wherein like reference numerals refer to like elements throughout.
FIG. 1 illustrates an example structure of a communications system.
The illustrated communications system 1 includes a carrier-side
communication apparatus 10 and a base station apparatus 20. The
carrier-side communication apparatus 10 includes a first upper node
13, a second upper node 14, and an upper communication control unit
15. The base station apparatus 20 includes a first communication
unit 21, a second communication unit 22, and a communication
control unit 23.
[0038] The first upper node 13 performs communication through first
communication sessions. The second upper node 14 performs
communication through second communication sessions. The second
upper node 14 is coupled to the first upper node 13. The upper
communication control unit 15 controls the carrier-side
communication apparatus 10 as a whole, including control of the
first upper node 13 and second upper node 14.
[0039] The first communication unit 21 communicates with the first
upper node 13 through a first communication session established
therewith. The second communication unit 22 communicates with the
second upper node 14 through a second communication session
established therewith. The second communication unit 22 is coupled
to the first communication unit 21. The communication control unit
23 controls the base station apparatus 20 as a whole, including
control of the first communication unit 21 and second communication
unit 22.
[0040] The communication control unit 23 and upper communication
control unit 15 work together to perform communication path
switching so as to use the second communication session to
transport a signal intended for the first communication session,
when the first communication session is disrupted, or when the
number of existing first communication sessions has exceeded a
given upper limit that the first upper node can handle. The latter
event is referred to herein as "excessive session count."
[0041] In operation, the first communication unit 21 detects
disruption of communication in its first communication session and
thus notifies the communication control unit 23 of the detected
communication disruption. The communication control unit 23
propagates this information to the upper communication control unit
15 by sending a communication disruption notice over a control
channel that conveys control signals between the carrier-side
communication apparatus 10 and base station apparatus 20.
[0042] Upon notification of the communication disruption concerning
the first communication session, the communication control unit 23
causes the first communication unit 21 and second communication
unit 22 to switch communication paths from the first communication
session to the second communication session, thus making the
traffic detour around the disrupted first communication session.
Also, upon receipt of the communication disruption notice
concerning the first communication session, the upper communication
control unit 15 causes the first upper node 13 and second upper
node 14 to switch communication paths from the first communication
session to the second communication session, thus making the
traffic detour around the disrupted first communication
session.
[0043] The first upper node 13 may also detect disruption of
communication in a first communication session. When this is the
case, the first upper node 13 notifies the upper communication
control unit 15 of the communication disruption. The upper
communication control unit 15 then propagates the information to
the communication control unit 23 via the control channel by
sending a communication disruption notice.
[0044] Upon notification of the communication disruption concerning
the first communication session, the upper communication control
unit 15 causes the first upper node 13 and second upper node 14 to
switch communication paths from the disrupted first communication
session to the second communication session, thus making the
traffic detour around the disrupted session. Also, upon receipt of
the communication disruption notice concerning the first
communication session, the communication control unit 23 causes the
first communication unit 21 and second communication unit 22 to
switch communication paths from the disrupted first communication
session to the second communication session, thus making the
traffic detour around the disrupted session.
[0045] Suppose now that the first communication unit 21 issues a
request for setting up a new first communication session. However,
if the number of existing first communication sessions has already
reached a given upper limit, the first upper node 13 is unable to
grant the request. The first upper node 13 thus informs the upper
communication control unit 15 of the excessive session count. The
upper communication control unit 15 then propagates the information
to the communication control unit 23 via a control channel.
[0046] The upper communication control unit 15 now recognizes that
the number of existing first communication sessions has reached its
upper limit. The upper communication control unit 15 thus causes
its local first upper node 13 and second upper node 14 to set up a
detour by performing communication path switching, i.e., using a
second communication session to transport signals intended for a
first communication session.
[0047] The communication control unit 23 also recognizes that the
number of existing first communication sessions has reached its
upper limit. The communication control unit 23 thus causes its
local first communication unit 21 and second communication unit 22
to set up a detour by performing communication path switching,
i.e., using a second communication session to transport signals
intended for a first communication session.
[0048] The above-described communications system 1 may be
implemented as a radio communications system that supports both 3G
and LTE technologies. The following section will describe a
structure and operation of such a radio communications system.
[0049] FIGS. 2 and 3 illustrate an example of overall structure of
the proposed radio communications system. The illustrated radio
communications system 1a includes a mobile communications carrier
10a, a dual femtocell 20, and a piece of user equipment (UE) 30
such as a mobile phone. It is noted that the mobile communications
carrier 10a provides functions of the foregoing carrier-side
communication apparatus 10. It is also noted that the dual
femtocell 20 is equivalent to the foregoing base station apparatus
20.
[0050] The mobile communications carrier 10a is connected to the
dual femtocell 20 via a network 40. This network 40 may be, for
example, a broadband network such as the Internet and intranet. The
network 40 may also include a public telephone network. The dual
femtocell 20 and UE 30 are connected wirelessly via radio
communication links.
[0051] The illustrated UE 30 is a radio communication device that
is compatible with both the 3G and LTE systems. While not seen in
FIGS. 2 and 3, the dual femtocell 20 may also serve other UE
devices dedicated to either 3G communication or LTE
communication.
[0052] To provide the UE 30 with communication services, the mobile
communications carrier 10a is formed from the following networks
and devices: a 3G core network 11, an LTE core network 12, a 3G
femtocell gateway (GW) 13, LTE femto gateway 14, and a femtocell
management server 15.
[0053] The femtocell management server 15 includes a Home Node-B
(HNB) management system (HMS) 15a. The HMS 15a has an interface to
communicate with each of the 3G femto gateway 13 and LTE femto
gateway 14. Also the 3G femto gateway 13 and LTE femto gateway 14
are connected to each other through their interface.
[0054] Specifically, the mobile communications carrier 10a includes
the following components:
(a1) 3G Core Network 11
[0055] The 3G core network 11 is a core network that acts as an
endpoint of 3G communication (i.e., terminates 3G communication
interface). The illustrated 3G core network 11 includes a mobile
switching center (MSC) 11a and a Serving GPPRS Support Node (SGSN)
11b, where GPRS stands for General Packet Radio Service. The MSC
11a is a core node device that acts as an endpoint or a switch of
3G voice communication. Control signals of the MSC 11a are referred
to as Iu-CS C-Plane, while U-Plane signals of voice communication
are referred to as Iu-CS U-Plane. The SGSN 11b is a core node
device that acts as an endpoint of 3G packet communication. Control
signals of the SGSN 11b for packet communication are referred to as
Iu-CS U-Plane, and U-Plane signals for packet communication are
referred to as Iu-PS U-Plane.
(a2) LTE Core Network 12
[0056] The LTE core network 12 is a core network that acts as an
endpoint of LTE communication. The LTE core network 12 includes a
Mobile Management Entity (MME) 12a and a Serving Gateway (S-GW)
12b. The MME12a is a core node device that acts as an endpoint of
control signals used in the LTE packet communication. Those control
signals are referred to as S1-MME. The S-GW 12b is a core node
device that acts as an endpoint of U-Plane signals in the LTE
packet communication. Those U-Plane signals are referred to as
S1-U.
(a3) 3G Femto Gateway 13
[0057] The 3G femto gateway 13 is a set of gateway facilities that
acts as endpoint of communication protocols used by Home Node B
(HNB). Here the term "HNB" refers to a femtocell based on the 3G
technology. The 3G femto gateway 13 includes an HNB-GW 13a and a
security gateway (SeGW) 13b for HNB-GW. The HNB-GW 13a is a gateway
that acts as an endpoint of communication with the 3G femtocell
unit 21 and forwards its signals to the MSC 11a and SGSN 11b at an
upper level. The interface between the HNB-GW 13a and 3G femtocell
unit 21 is named Iuh. More specifically, control signals for voice
communication are referred to as Iuh-CS C-Plane. U-Plane signals
for voice communication are referred to as Iuh-CS U-Plane. Control
signals for packet communication are referred to as Iuh-PS C-Plane.
U-Plane signals for packet communication are referred to as Iuh-PS
U-Plane.
[0058] The HNB-GW 13a also acts as an endpoint of interface to the
HeNB-GW 14a in the LTE femto gateway 14. The HNB-GW 13a may further
receive a session switching command sent from an HMS 15a in the
femtocell management server 15 and provides the HMS 15a with
information on the state of sessions and the like.
(a4) SeGW 13b for HNB-GW
[0059] The SeGW 13b for HNB-GW is a security gateway that
communicates with the 3G femtocell unit 21 in the dual femtocell 20
via a network 40. Security gateways are network devices that enable
secure communication between two networks that use different
protocols. In general, encrypted communication functions such as
the Security Architecture for Internet Protocol (IPsec) are
implemented in security gateways. The SeGW 13b for HNB-GW
establishes an IPsec session to a session termination unit 21a in
the 3G femtocell unit 21.
(a5) LTE Femto Gateway 14
[0060] The LTE femto gateway 14 is a set of gateway facilities to
terminate communication protocols of Home eNode B (HeNB), i.e., a
femtocell based on the LTE technology. The LTE femto gateway 14
includes a HeNB-GW 14a and an SeGW 14b for HeNB.
[0061] The HeNB-GW 14a is a gateway that acts as an endpoint of
communication with the LTE femtocell unit 22 and forwards signals
to the MME 12a and S-GW 12b at an upper level. The interface
between the HeNB-GW 14a and LTE femtocell unit 22 is called S1.
More specifically, control signals for packet communication are
referred to as S1-MME. U-Plane signals for packet communication are
referred to as S1-U.
[0062] The HeNB-GW 14a also acts as an endpoint of the interface to
HNB-GW 13a in the 3G femto gateway 13. Further the HeNB-GW 14a may
receive a session switching command sent from an HMS 15a in the
femtocell management server 15 and provides the HMS 15a with
information on the state of sessions and the like.
[0063] The SeGW 14b for HeNB-GW is a security gateway that
communicates with the LTE femtocell unit 22 in the dual femtocell
20 via the network 40. The SeGW 14b for HeNB-GW establishes an
IPsec session to a session termination unit 22a in the LTE
femtocell unit 22.
(a6) Femtocell Management Server 15
[0064] The femtocell management server 15 is a maintenance and
management node that is deployed to manage a plurality of dual
femtocells including the illustrated femtocell 20. The femtocell
management server 15 includes an HMS 15a and an SeGW 15b for
HMS.
[0065] The HMS 15a communicates with a management unit 23 in the
dual femtocell 20 by using control protocols such as TR-069 to
control, for example, the procedure of session switching between 3G
communication paths and LTE communication paths. The functions of
HMS are specified in relevant standard specifications and this
description does not describe their details. TR-069 is a technical
specification of Broadband Forum, entitled "CPE WAN Management
Protocol." CPE stands for "customer premises equipment," and WAN
means "wide area network."
[0066] The SeGW 15b for HMS is a security gateway that communicates
with a management unit 23 in the dual femtocell 20 via the network
40. Specifically, the SeGW 15b for HMS establishes an IPsec session
to a session termination unit 23a in the management unit 23.
[0067] Referring now to FIG. 3, the components of the dual
femtocell 20 will be described below. The dual femtocell 20 is a
subminiature base station designed for use in home, office, and
commercial environments to enable simultaneous communication of up
to about four users. The dual femtocell 20 supports both the 3G and
LTE technologies.
[0068] The dual femtocell 20 includes a 3G femtocell unit 21, an
LTE femtocell unit 22, and a management unit 23. The 3G femtocell
unit 21 and LTE femtocell unit 22 have an interface to communicate
with a control unit 23b in the management unit 23. Also the 3G
femtocell unit 21 and LTE femtocell unit 22 have an interface
between their respective protocol termination units 21b and
22b.
(b1) 3G Femtocell Unit 21
[0069] The 3G femtocell unit 21 is a collection of functions
necessary for providing 3G-based communication. Specifically, the
3G femtocell unit 21 includes a session termination unit 21a, a
protocol termination unit 21b, and a radio unit 21c, as will be
detailed below.
[0070] The session termination unit 21a is a security gateway
coupled to the network 40 for communication with the HNB-GW 13a in
the 3G femto gateway 13 at an upper level. The session termination
unit 21a establishes an IPsec session to the SeGW 13b for HNB-GW in
the 3G femto gateway 13.
[0071] The protocol termination unit 21b is a functional block that
terminates protocols of Iuh interface. Specifically, the protocol
termination unit 21b terminates Iuh-CS C-Plane, Iuh-CS U-Plane,
Iuh-PS C-Plane, and Iuh-PS U-Plane. The protocol termination unit
21b also terminates an HNB/HeNB interface to the protocol
termination unit 22b in the LTE femtocell unit 22. The protocol
termination unit 21b may further receive a session switching
command from the control unit 23b in the management unit 23 and
provides the control unit 23b with information on the state of
sessions and the like.
[0072] The radio unit 21c is a functional block that performs
wireless communication by using the 3G technology to communicate
with the UE 30, which supports both 3G and LTE, as well as with
ordinary 3G UE (not illustrated). This wireless interface is
referred to as Uu in the 3GPP standard (details are omitted
here).
(b2) LTE Femtocell Unit 22
[0073] The LTE femtocell unit 22 is a collection of functions
necessary for providing LTE-based communication. Specifically, the
LTE femtocell unit 22 includes a session termination unit 22a, a
protocol termination unit 22b, and a radio unit 22c, as will be
detailed below.
[0074] The session termination unit 22a is a security gateway
coupled to the network 40 for communication with the HeNB-GW 14a in
the LTE femto gateway 14 at an upper level. The session termination
unit 22a establishes an IPsec session to the SeGW 14b for HeNB-GW
in the LTE femto gateway 14.
[0075] The protocol termination unit 22b is a functional block that
terminates protocols of S1 interface. Specifically, the protocol
termination unit 22b terminates S1-MME and S1-U. The protocol
termination unit 22b also terminates an HNB-HeNB interface to the
protocol termination unit 21b in the 3G femtocell unit 21. The
protocol termination unit 22b may further receive a session
switching command from the control unit 23b in the management unit
23 and provides the control unit 23b with information on the state
of sessions and the like.
[0076] The radio unit 22c is a functional block that performs
wireless communication by using the LTE technology to communicate
with the UE 30, which supports both 3G and LTE, as well as with
ordinary UE designed for LTE communication (not illustrated). This
wireless interface is referred to as LTE-Uu in the 3GPP standard
(details are omitted here).
(b3) Management Unit 23
[0077] The management unit 23 communicates with the femtocell
management server 15 at the upper level by using TR-069 protocol
and the like to send status of sessions and receive session
switching commands. The management unit 23 also sends session
switching commands to the 3G femtocell unit 21 and LTE femtocell
unit 22 and, in response, receives information on the state of
sessions.
[0078] The session termination unit 23a is a security gateway
coupled to the network 40 for communication with the HMS 15a in the
femtocell management server 15 at the upper level. The session
termination unit 23a establishes an IPsec session to the SeGW 15b
for HMS in the femtocell management server 15.
[0079] The control unit 23b communicates with the protocol
termination unit 21b in the 3G femtocell unit 21, as well as with
the protocol termination unit 22b in the LTE femtocell unit 22, to
control, for example, a procedure of session switching between the
3G and LTE systems.
[0080] The UE 30 is formed from the components described below. The
UE 30 is an example implementation of user equipment that enables
the user to access network services through a dual femtocell 20. In
addition to this UE 30, other UE devices dedicated to either 3G or
LTE may also be used for communication of voice and other signal
traffic over the network 40. Referring to FIG. 3, the UE 30
includes a 3G communication unit 31, an LTE communication unit 32,
and an upper-level application 33.
(c1) 3G Communication Unit 31
[0081] The 3G communication unit 31 is a functional block that
performs communication by using the 3G technology. The 3G
communication unit 31 includes a radio unit 31a which terminates 3G
radio interface Uu (details are omitted here).
(c2) LTE Communication Unit 32
[0082] The LTE communication unit 32 is a functional block that
performs communication by using the LTE technology. The LTE
communication unit 32 includes a radio unit 32a which terminates
LTE radio interface LTE-Uu (details are omitted here).
(c3) Upper-Level Application 33
[0083] The upper-level application 33 is a function block that
performs processing above the wireless layer (details are omitted
here).
[0084] The following section will now provide details about
operation of the radio communications system 1a. In the proposed
radio communications system 1a, the dual femtocell 20, HNB-GW 13a,
and HeNB-GW 14a have a function to detect disruption of
communication. They achieve the switching of communication paths by
interacting with each other through an HMS 15a. The HMS 15a is
designed to distribute workload of communication services by
collecting information about the amount of communication traffic in
the 3G femto gateway 13 and LTE femto gateway 14 and redirecting a
denied connection (if any) towards a gateway that is loaded with a
smaller amount of traffic.
[0085] For example, the radio communications system 1a switches
communication paths in response to detection of communication
disruption or excessive session. The radio communications system 1a
also sets up redundant communication paths. The following
description will provide more specific examples of operation.
[0086] First, with respect to the functions of switching from an
LTE communication path to a 3G communication path, the following
three cases will be discussed: (1) LTE communication using a
3G-side communication path when disruption of communication is
detected in the dual femtocell 20, (2) LTE communication using a
3G-side communication path when disruption of communication is
detected at the HeNB-GW 14a, (3) LTE communication using a 3G-side
communication path when an excessive session count is detected at
the HeNB-GW 14a or SeGW 14b for HeNB-GW.
[0087] Second, with respect to the functions of switching from a 3G
communication path to an LTE communication path, the following
three cases will be discussed: (4) 3G communication using an
LTE-side communication path when disruption of communication is
detected in the dual femtocell 20, (5) 3G communication using an
LTE-side communication path when disruption of communication is
detected at the HNB-GW 13a, (6) 3G communication using an LTE-side
communication path when an excessive session count is detected at
the HNB-GW 13a or SeGW 13b for HNB-GW.
[0088] Third, with respect to setup of redundant communication
paths, the following two cases will be discussed: (7) LTE
communication using a 3G-side communication path for redundancy
purposes, and (8) 3G communication using an LTE-side communication
path for redundancy purposes. Each of the above cases (1) to (8)
will be discussed below.
[0089] (1) LTE communication using 3G-side communication path
[0090] FIG. 4 illustrates a sequence of LTE communication using a
3G-side communication path, which performs an LTE-to-3G switchover
of communication paths when disruption of communication is detected
at the dual femtocell 20.
[0091] (S1) The protocol termination unit 22b in the LTE femtocell
unit 22 detects disruption of communication.
[0092] (S2a-S2b) The protocol termination unit 22b notifies the
control unit 23b in the management unit 23 of the communication
disruption by sending a communication disruption notice (simply
"disruption notice" in FIG. 4 and other figures).
[0093] (S3a-S3e) The control unit 23b forwards this communication
disruption notice to the HMS 15a. The HMS 15a then sends a session
switching request to the HNB-GW 13a and HeNB-GW 14a.
[0094] (S4a-S4b) The control unit 23b sends a session switching
request to the protocol termination unit 21b.
[0095] (S5a) The protocol termination unit 22b sends the protocol
termination unit 21b an uplink packet addressed to the HeNB-GW
14a.
[0096] (S5b) The protocol termination unit 21b encapsulates the
above packet into an Iuh packet and sends it to the HNB-GW 13a.
[0097] (S5c) The HNB-GW 13a decapsulates the above packet and
forwards the contained packet to the HeNB-GW 14a.
[0098] (S5d) Similarly to the uplink described above, a downlink
packet is sent from the HeNB-GW 14a to the protocol termination
unit 22b via the HNB-GW 13a and protocol termination unit 21b.
[0099] The above-described sequence provides a 3G-side
communication path as an alternative path when disruption of
communication is detected at the LTE femtocell unit 22. The LTE
communication can thus continue its operation with the new
path.
[0100] (2) LTE communication using 3G-side communication path when
disruption of communication is detected at HeNB-GW 14a
[0101] FIG. 5 illustrates another sequence of LTE communication
using a 3G-side communication path, which performs an LTE-to-3G
switchover of communication paths when disruption of communication
is detected at the HeNB-GW 14a.
[0102] (S11) The HeNB-GW 14a detects disruption of
communication.
[0103] (S12a-S12b) The HeNB-GW 14a notifies the HMS 15a of the
communication disruption by sending a communication disruption
notice.
[0104] (S13a-S13f) The HMS 15a forwards this communication
disruption notice to the control unit 23b. The control unit 23b
then sends a session switching request to the protocol termination
units 21b and 22b.
[0105] (S14a-S14b) The HMS 15a sends a session switching request to
the HNB-GW 13a.
[0106] (S15a-S15d) Uplink and downlink packets are transported
between the protocol termination unit 22b and HeNB-GW 14a similarly
to steps S5a to S5d discussed above in FIG. 4.
[0107] The above-described sequence provides a 3G-side
communication path as an alternative path when disruption of
communication is detected at the HeNB-GW 14a. The LTE communication
can thus continue its operation with the new path.
[0108] (3) LTE communication using 3G-side communication path when
excessive session count is detected in HeNB-GW 14a or SeGW 14b for
HeNB-GW
[0109] FIG. 6 illustrates yet another sequence of LTE communication
using a 3G-side communication path, which performs an LTE-to-3G
switchover of communication paths when an excessive session count
is detected at the HeNB-GW 14a.
[0110] (S21a-S21b) The SeGW 14b for HeNB-GW forwards a session
setup request from the protocol termination unit 22b to the HeNB-GW
14a. The HeNB-GW 14a, however, detects an excessive session count
(or detects that the total amount of traffic exceeds its upper
limit).
[0111] (S22a-S22d) The HeNB-GW 14a thus sends an excessive session
notice to the HMS 15a, and the HMS 15a propagates it to the control
unit 23b.
[0112] (S23a-S23d) The control unit 23b sends a session switching
request to the protocol termination units 21b and 22b.
[0113] (S24a-S24b) The HMS 15a sends a session switching request to
the HNB-GW 13a.
[0114] (S25a-S25d) Uplink and downlink packets are transported
between the protocol termination unit 22b and HeNB-GW 14a similarly
to steps S5a to S5d discussed above in FIG. 4.
[0115] The above-described communication sequence provides a
3G-side communication path to distribute the traffic load when an
excessive session count is detected at the HeNB-GW 14a. The LTE
communication can thus continue its operation with the provided
path.
[0116] FIG. 7 illustrates still another sequence of LTE
communication using a 3G-side communication path, which performs an
LTE-to-3G switchover of communication paths when an excessive
session count is detected at the SeGW 14b for HeNB-GW.
[0117] (S31a-S31b) The SeGW 14b for HeNB-GW receives a session
setup request from the session termination unit 22a. The SeGW 14b
for HeNB-GW, however, detects an excessive session count (or
detects that the total amount of traffic exceeds its upper
limit).
[0118] (S32a-S32d) The SeGW 14b for HeNB-GW thus sends an excessive
session notice to the HMS 15a, and the HMS 15a propagates it to the
control unit 23b.
[0119] (S33a-S33d) The control unit 23b sends a session switching
request to the protocol termination units 21b and 22b.
[0120] (S34a-S34b) The HMS 15a sends a session switching request to
the HNB-GW 13a.
[0121] (S35a-S35d) Uplink and downlink packets are transported
between the protocol termination unit 22b and HeNB-GW 14a similarly
to steps S5a to S5d discussed above in FIG. 4.
[0122] The above-described communication sequence provides a
3G-side communication path to distribute the traffic load when an
excessive session count is detected at the SeGW 14b for HeNB-GW.
The LTE communication can thus continue its operation with the
provided path.
[0123] (4) 3G communication using LTE-side communication path when
disruption of communication is detected in dual femtocell 20
[0124] FIG. 8 illustrates a sequence of 3G communication using an
LTE-side communication path, which performs a 3G-to-LTE switchover
of communication paths when disruption of communication is detected
in the dual femtocell 20.
[0125] (S41) The protocol termination unit 21b in the 3G femtocell
unit 21 detects disruption of communication.
[0126] (S42a-S42b) The protocol termination unit 21b notifies the
control unit 23b in the management unit 23 of the communication
disruption by sending a communication disruption notice.
[0127] (S43a-S43f) The control unit 23b forwards this communication
disruption notice to the HMS 15a. The HMS 15a then sends a session
switching request to the HeNB-GW 14a and HNB-GW 13a.
[0128] (S44a-S44b) The control unit 23b sends a session switching
request to the protocol termination unit 22b.
[0129] (S45a) The protocol termination unit 21b sends the protocol
termination unit 22b an uplink packet addressed to the HNB-GW
13a.
[0130] (S45b) The protocol termination unit 22b encapsulates this
uplink packet into an S1 packet and sends it to the HeNB-GW
14a.
[0131] (S45c) The HeNB-GW 14a decapsulates the above packet and
forwards the contained packet to the HNB-GW 13a.
[0132] (S45d) Similarly to the uplink packet described above, a
downlink packet is sent from the HNB-GW 13a to the protocol
termination unit 21b via the HeNB-GW 14a and protocol termination
unit 22b.
[0133] The above-described sequence provides an LTE-side
communication path as an alternative path when disruption of
communication is detected at the 3G femtocell unit 21. The 3G
communication can thus continue its operation with the new
path.
[0134] (5) 3G communication using LTE-side communication path when
disruption of communication is detected at HNB-GW 13a
[0135] FIG. 9 illustrates another sequence of 3G communication
using an LTE-side communication path, which performs a 3G-to-LTE
switchover of communication paths when disruption of communication
is detected at the HNB-GW 13a.
[0136] (S51) The HNB-GW 13a detects disruption of
communication.
[0137] (S52a-S52b) The HNB-GW 13a notifies the HMS 15a of the
communication disruption by sending a communication disruption
notice.
[0138] (S53a-S53f) The HMS 15a forwards this communication
disruption notice to the control unit 23b. The control unit 23b
then sends a session switching request to the protocol termination
units 21b and 22b.
[0139] (S54a-S54b) The HMS 15a sends a session switching request to
the HeNB-GW 14a.
[0140] (S55a-S55d) Uplink and downlink packets are transported
between the protocol termination unit 21b and HNB-GW 13a similarly
to steps S45a to S45d discussed above in FIG. 8.
[0141] The above-described sequence provides an LTE-side
communication path as an alternative path when disruption of
communication is detected at the HNB-GW 13a. The 3G communication
can thus continue its operation with the new path.
[0142] (6) 3G communication using LTE-side communication path when
excessive session count is detected in HNB-GW 13a or SeGW 13b for
HNB-GW
[0143] FIG. 10 illustrates yet another sequence of 3G communication
using an LTE-side communication path, which performs a 3G-to-LTE
switchover of communication paths when an excessive session count
is detected at the HNB-GW 13a.
[0144] (S61a-S61b) The SeGW 13b for HNB-GW forwards a session setup
request from the session termination unit 21a to the HNB-GW 13a.
The HNB-GW 13a, however, detects an excessive session count (or
detects that the total amount of traffic has already reached its
upper limit).
[0145] (S62a-S62d) The HNB-GW 13a thus sends an excessive session
notice to the HMS 15a, and the HMS 15a propagates it to the control
unit 23b.
[0146] (S63a-S63d) The control unit 23b then sends a session
switching request to the protocol termination units 21b and
22b.
[0147] (S64a-S64b) The HMS 15a sends a session switching request to
the HeNB-GW 14a.
[0148] (S65a-S65d) Uplink and downlink packets are transported
between the protocol termination unit 21b and HNB-GW 13a similarly
to steps S45a to S45d discussed above in FIG. 8.
[0149] The above-described communication sequence provides an
LTE-side communication path to distribute the traffic load when an
excessive session count is detected at the HNB-GW 13a. The 3G
communications can thus continue its operation with the provided
path.
[0150] FIG. 11 illustrates still another sequence of 3G
communication using an LTE-side communication path, which performs
a 3G-to-LTE switchover of communication paths when an excessive
session count is detected at the SeGW 13b for HNB-GW.
[0151] (S71a-S71b) The SeGW 13b for HNB-GW receives a session setup
request from the session termination unit 21a. The SeGW 13b for
HNB-GW, however, detects an excessive session count (or detects
that the total amount of traffic exceeds its upper limit).
[0152] (S72a-S72d) The SeGW 13b for HNB-GW thus sends an excessive
session notice to the HMS 15a, and the HMS 15a propagates it to the
control unit 23b.
[0153] (S73a-S73d) The control unit 23b then sends a session
switching request to the protocol termination units 21b and
22b.
[0154] (S74a-S74b) The HMS 15a sends a session switching request to
the HeNB-GW 14a.
[0155] (S75a-S75d) Uplink and downlink packets are transported
between the protocol termination unit 21b and HNB-GW 13a similarly
to steps S45a to S45d discussed above in FIG. 8.
[0156] The above-described communication sequence provides an
LTE-side communication path to distribute the traffic load when an
excessive session count is detected at the SeGW 13b for HNB-GW. The
3G communication can thus continue its operation with the provided
path.
[0157] (7) LTE communication using 3G-side communication paths for
redundancy purposes
[0158] FIG. 12 illustrates a sequence of LTE communication using a
3G-side communication path as a redundant communication path.
[0159] (S81) The dual femtocell 20 starts up, causing its protocol
termination unit 22b to start LTE communication with the HeNB-GW
14a.
[0160] (S82a-S82b) The protocol termination unit 22b sends a
redundant path setup request (simply "redundant path request" in
FIG. 12 and subsequent figures) to the control unit 23b in the
management unit 23.
[0161] (S83a-S83f) The control unit 23b forwards this redundant
path setup request to the HMS 15a, and the HMS 15a propagates it to
the HNB-GW 13a and HeNB-GW 14a.
[0162] (S84a-S84b) The control unit 23b sends a redundant path
setup request to the protocol termination unit 21b.
[0163] (S85a) The protocol termination unit 22b sends the protocol
termination unit 21b an uplink packet addressed to the HeNB-GW 14a.
(The same packet is also transmitted over a 3G communication
path.)
[0164] (S85b) The protocol termination unit 21b encapsulates the
above packet into an Iuh packet and sends it to the HNB-GW 13a.
[0165] (S85c) The HNB-GW 13a decapsulates the above packet and
forwards the contained packet to the HeNB-GW 14a.
[0166] (S85d) Similarly to the uplink packet described above, a
downlink packet is sent from the HeNB-GW 14a to the protocol
termination unit 22b via the HNB-GW 13a and protocol termination
unit 21b.
[0167] The above-described communication sequence establishes a 3G
communication path, in addition to an LTE communication path, when
the dual femtocell 20 starts up for LTE communication. The mobile
communications carrier 10a and dual femtocell 20 can thus be
connected by both 3G and LTE paths to transport packets of LTE
communication. This means that the LTE communication path is
protected by a redundant 3G communication path, making it possible
to continue ongoing communication even if the LTE communication
path encounters disruption. That is, the same packets are
transmitted over two paths, one for normal use and the other for
backup use in case of disruption. The network system can therefore
recover from communication disruption and other failures more
quickly.
[0168] (8) 3G communication using LTE-side communication paths for
redundancy purposes
[0169] FIG. 13 illustrates a sequence of 3G communication using an
LTE-side communication path as a redundant communication path.
[0170] (S91) The dual femtocell 20 starts up, causing its protocol
termination unit 21b to start 3G communication with the HNB-GW
13a.
[0171] (S92a-S92b) The protocol termination unit 21b sends a
redundant path setup request to the control unit 23b in the
management unit 23.
[0172] (S93a-S93f) The control unit 23b forwards this redundant
path setup request to the HMS 15a, and the HMS 15a propagates it to
the HeNB-GW 14a and HNB-GW 13a.
[0173] (S94a-S94b) The control unit 23b sends a redundant path
setup request to the protocol termination unit 22b.
[0174] (S95a) The protocol termination unit 21b sends the protocol
termination unit 22b an uplink packet addressed to the HNB-GW 13a.
(The same packet is also transmitted over an LTE communication
path.)
[0175] (S95b) The protocol termination unit 22b encapsulates this
uplink packet into an S1 packet and sends it to the HeNB-GW
14a.
[0176] (S95c) The HeNB-GW 14a decapsulates the above packet and
forwards the contained packet to the HNB-GW 13a.
[0177] (S95d) Similarly to the uplink packet described above, a
downlink packet is sent from the HNB-GW 13a to the protocol
termination unit 21b via the HeNB-GW 14a and protocol termination
unit 22b.
[0178] The above-described communication sequence establishes an
LTE communication path, in addition to a 3G communication path,
when the dual femtocell 20 starts up for 3G communication. The
mobile communications carrier 10a and dual femtocell 20 can thus be
connected by both 3G and LTE paths to transport packets of 3G
communication. This means that the 3G communication path is
protected by a redundant LTE communication path, making it possible
to continue ongoing communication even the 3G communication path
encounters disruption. That is, the same packets are transmitted
over two paths, one for normal use and the other for backup use in
case of disruption. The network system can therefore recover from
communication disruption and other failures more quickly.
[0179] The proposed network system uses various messages. Those
messages are composed in accordance with some specific message
formats that define how to organize the content data. The following
section will describe several examples of such message formats.
[0180] FIG. 14 illustrates a data format of a communication
disruption notice. The illustrated communication disruption notice
message m1 is formed from the following data fields: Message Name,
Disrupted Node Name, Femtocell-side Connection Data, and Femto
GW-side Connection Data.
[0181] For example, the Message Name field contains a value of
"Communication Disruption Notice." The Disrupted Node Name field
contains a value of "HeNB-GW" or "HNB-GW" or "3G Femtocell" or "LTE
Femtocell." The femtocell-side connection data field contains as
much connection setup data as necessary for a femtocell, which may
include: Internet Protocol (IP) address, port number, point code of
Stream Control Transmission Protocol (SCTP), and Tunnel Endpoint
Identifier (TEID) of General Packet Radio Service (GPRS) Tunneling
Protocol-User plane (GTP-U). The femto GW-side connection data
field contains as much connection setup data as necessary for a
femto gateway, which may include: IP address, port number, point
code of SCTP, and TEID of GTP-U.
[0182] FIG. 15 illustrates a data format of a response to the
communication disruption notice. The illustrated response message
m1r to communication disruption notice is formed from the following
data fields: Message Name, Source Node Name, and Connection
Result.
[0183] For example, the Message Name field contains a value of
"Response to Communication Disruption Notice." The Source Node Name
field contains a value of "HeNB-GW" or "HNB-GW" or "3G Femtocell"
or "LTE Femtocell" or "HMS." The Connection Result field contains a
value of either "Done" or "Failed."
[0184] FIG. 16 illustrates a data format of a session switching
request. The illustrated session switching request message m2 is
formed from the following data fields: Message Name, Disrupted Node
Name, Femtocell-side Connection Data, and Femto GW-side Connection
Data.
[0185] For example, the Message Name Field contains a value of
"Session Switching Request." The Disrupted Node Name field contains
a value of "HeNB-GW" or "HNB-GW" or "3G Femtocell" or "LTE
Femtocell."
[0186] The femto GW-side connection data field contains as much
connection setup data as necessary for a femto gateway, which may
include: IP address, port number, point code of SCTP, and TEID of
GTP-U. The femto GW-side connection data field contains as much
connection setup data as necessary for a femto gateway, which may
include: IP address, port number, point code of SCTP, and TEID of
GTP-U.
[0187] The session switching request message m2 is sent by the HMS
15a or control unit 23b when either has received a communication
disruption notice or an excessive session notice. Accordingly the
femtocell-side connection data and femto GW-side connection data
fields of this session switching request message m2 are populated
with the corresponding values stored in the communication
disruption notice or excessive session notice that has just been
received.
[0188] FIG. 17 illustrates a data format of a response to a session
switching request. The illustrated response message m2r of session
switching request is formed from the following data fields: Message
Name, Source Node Name, and Connection Result.
[0189] For example, the Message Name field contains a value of
"Response to Session Switching Request." The Source Node Name field
contains a value of "HeNB-GW" or "HNB-GW" or "3G Femtocell" or "LTE
Femtocell" or "HMS." The Connection Result field contains a value
of either "Done" or "Failed."
[0190] FIG. 18 illustrates a data format of an excessive session
notice. The illustrated excessive session notice message m3 is
formed from the following data fields: Message Name, Transmit Node
Name, Initiating Event, Femtocell-side Connection Data, and Femto
GW-side Connection Data.
[0191] For example, the Message Name field contains a value of
"Excessive Session Notice." The Source Node Name field contains a
value of "HeNB-GW" or "HNB-GW" or "SeGW for HNB-GW" or "SeGW for
HeNB-GW." The Initiating Event field contains a value indicating
either excessive session or total traffic exceeding upper limit, or
others.
[0192] The femtocell-side connection data field contains as much
connection setup data as necessary for a femtocell, which may
include: IP address, port number, point code of SCTP, and TEID of
GTP-U. The femto GW-side connection data field contains as much
connection setup data as necessary for a femto gateway, which may
include: IP address, port number, point code of SCTP, and TEID of
GTP-U.
[0193] FIG. 19 illustrates a data format of a response to an
excessive session notice. The illustrated response message m3r of
an excessive session notice is formed from the following data
fields: Message Name, Source Node Name, and Connection Result.
[0194] For example, the Message Name field contains a value of
"Response to Excessive Session Notice." The Source Node Name field
contains a value of "HeNB-GW" or "HNB-GW" or "3G Femtocell" or "LTE
Femtocell" or "HMS" to indicate the message sender's own node name.
The Connection Result field contains a value of either "Done" or
"Failed."
[0195] FIG. 20 illustrates a data format of a redundant path setup
request. The illustrated redundant path setup request message m4 is
formed from the following data fields: Message Name, Transmit Node
Name, Femtocell-side Connection Data, and Femto GW-side Connection
Data.
[0196] For example, the Message Name field contains a value of
"Redundant Path Setup Request." The Transmit Node Name field
contains a value of "HeNB-GW" or "HNB-GW" or "3G Femtocell" or "LTE
Femtocell." The femtocell-side connection data field contains as
much connection setup data as necessary for a femtocell, which may
include: IP address, port number, point code of SCTP, and TEID of
GTP-U. The femto GW-side connection data field contains as much
connection setup data as necessary for a femto gateway, which may
include: IP address, port number, point code of SCTP, and TEID of
GTP-U.
[0197] FIG. 21 illustrates a data format of a response to a
redundant path setup request. The illustrated response message m4r
of redundant path setup request is formed from the following data
fields: Message Name, Source Node Name, and Connection Result.
[0198] For example, the Message Name field contains a value of
"Response to Redundant Path Setup Request." The Source Node Name
field contains a value of "HeNB-GW" or "HNB-GW" or "3G Femtocell"
or "LTE Femtocell" or "HMS." The Connection Result field contains a
value of either "Done" or "Failed."
[0199] FIG. 22 illustrates a data format of control messages. The
HMS 15a and control unit 23b use control messages of TR-069 since
the 3GPP standard requires them to use the TR-069 protocols in
their communication. Specifically, FIG. 22 illustrates a data
format of Inform message m5 according to TR-069, which applies to
the signaling of a communication disruption notice, a response to
communication disruption notice, a redundant path setup request,
and a response to redundant path setup request.
[0200] More specifically, Inform message m5 is formed from the
following data fields ("Arguments" in the TR-069 specification):
DeviceId, Event, MaxEnvelopes, CurrentTime, RetryCount, and
ParameterList. For example, the Deviceld field contains a device
identifier of a dual femtocell that supports both the 3G and LTE
technologies. The Event field may contain, for example, a value of
four to indicate a VALUE CHANGE event. The MaxEnvelopes field is
set to a fixed value of one. The CurrentTime field indicates the
transmit date and time. The RetryCount field may be set to any
values. The ParameterList field is given a value that indicates
communication disruption notice, or response to communication
disruption notice, or redundant path setup request, or response to
redundant path setup request.
[0201] While various messages have been described above, the
proposed network system may transmit other messages over new paths
according to the present embodiment. Those messages may have any
appropriate data format since they are not particularly specified
in the 3GPP standard.
[0202] Protocols used in the proposed network system are organized
in a layered structure referred to as the protocol stack. For
example, FIG. 23 illustrates protocol stacks of Iuh. The bold
frames indicate stack elements that are different from existing
ones. Iuh interface is organized by the following protocol stacks:
Iu-CS C-Plane, Iu-CS U-Plane, Iu-PS C-Plane, Iu-PS U-Plane, S1-MME
over Iuh, and S1-U over Iuh. Here, the protocol stacks of Iu-CS
C-Plane, Iu-CS U-Plane, Iu-PS C-Plane, and Iu-PS U-Plane are
similar to those of existing systems.
[0203] Specifically, Iu-CS C-Plane and Iu-PS C-Plane are both
formed from layers of Ethernet.RTM., IP, SCTP, RANAP User
Adaptation layer (RUA), Radio Access Network Application Part
(RANAP), Mobility Management (MM), and Call Control (CC) layers in
that order, from bottom to top. Iu-CS U-Plane is a stack of layers
of Ethernet, IP, User Datagram Protocol (UDP), Real Time Transport
Protocol (RTP), Iu User Plane (IuUP), and DATA in that order, from
bottom to top. Iu-PS U-Plane and S1-U over Iuh are both formed from
the layers of Ethernet, IP, UDP, GTP-U, IP, DATA, and DATA in that
order, from bottom to top. S1-MME over Iuh is a stack of layers of
Ethernet, IP, SCTP, RUA, S1-AP, and GPRS Mobility
Management/Session Management (GMM/SM) in that order, from bottom
to top.
[0204] FIG. 24 illustrates protocol stacks of S1. The bold frames
indicate stack elements that are different from existing ones. S1
interface is organized by the following protocol stacks: S1-MME,
S1-U, Iuh-CS C-Plane over S1, Iuh-CS U-Plane over S1, Iuh-PS
C-Plane over S1, and Iuh-PS U-Plane over S1. Here, the protocol
stack S1-U is similar to that of existing systems, as is Iuh-PS
U-Plane over S1.
[0205] Specifically, S1-MME is a stack of layers including
Ethernet, IP, SCTP, S1-AP, and GMM/SM in that order, from bottom to
top. S1-U and Iuh-PS U-Plane over S1 are both formed from the
layers of Ethernet, IP, UDP, GTP-U, IP, DATA, and DATA in that
order, from bottom to top. Iuh-CS C-Plane over S1 and Iuh-PS
C-Plane over S1 are both formed from the layers of Ethernet, IP,
SCTP, S1-AP, RUA, RANAP, MM, and CC in that order, from bottom to
top. Iuh-CS U-Plane over S1 is a stack of layers including
Ethernet, IP, UDP, GTP-U, RTP, IuUP, and DATA in that order, from
bottom to top.
[0206] FIG. 25 illustrates a protocol stack of the control
interface between the HMS 15a and control unit 23b. This control
interface TR-069 is a stack of layers including Ethernet, IP,
Transmission Control Protocol (TCP), SSL Protocol Version
3.0/RFC2246--The TLS Protocol Version 1.0 (SSL/TLS), RFC
2616--Hypertext Transfer Protocol (HTTP), Simple Object Access
Protocol (SOAP), Remote Procedure Call (RPC) Methods, and DATA in
that order, from bottom to top.
[0207] Various features of the embodiments have been discussed
above. Those features make it possible to improve the quality of
communication.
[0208] All examples and conditional language recited herein are
intended for pedagogical purposes to aid the reader in
understanding the invention and the concepts contributed by the
inventor to furthering the art, and are to be construed as being
without limitation to such specifically recited examples and
conditions, nor does the organization of such examples in the
specification relate to a showing of the superiority and
inferiority of the invention. Although the embodiments of the
present invention have been described in detail, it should be
understood that various changes, substitutions, and alterations
could be made hereto without departing from the spirit and scope of
the invention.
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